We’ve collected these identifiers and namespaces as a single object, a concordance, which empowers a user to reference each source. You can think of it as a mapping of an identifier in a namespace to its equivalent in another namespace. But it’s not a joining of information; we’re only enumerating the identifiers, not the back-end data or attributes that they describe.

The last sentence is important. The service is agnostic on the data model or ontologies used by the various identifiers publishers. Ontological emptiness makes the service useful.

Another striking example is provided by Ellerdale, reconciliating Wikipedia or Freebase topics with Twitter hashtags to build amazing dynamic pages.

Let's guess that many more of the same will emerge in the months to come.